Amelogenesis imperfecta: prevalence and incidence in a northern Swedish county

Bäckman, Birgitta; Holm, Anna

doi:10.1111/j.1600-0528.1986.tb01493.x

Cited by 189 publications

(135 citation statements)

References 12 publications

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“…Hypoplastic (thin but seemingly correctly mineralized) or hypomineralized enamel are the most common types of AI seen in humans, but an overlap of these characteristics is often present. 5 The abnormal enamel layer in Fam20a -/-and Fam20c -/-mice appears to form a weak, poorly mineralized crust that crumbles and is lost during mastication. In both lines, there is disruption of the mineralization front and rod formation at the secretory surface of the ameloblast, where the organization and elongation of enamel into rods is established.…”

Section: Discussionmentioning

confidence: 99%

Amelogenesis Imperfecta and Other Biomineralization Defects in Fam20a and Fam20c Null Mice

et al. 2012

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The FAM20 family of secreted proteins consists of three members (FAM20A, FAM20B, and FAM20C) recently linked to developmental disorders suggesting roles for FAM20 proteins in modulating biomineralization processes. The authors report here findings in knockout mice having null mutations affecting each of the three FAM20 proteins. Both Fam20a and Fam20c null mice survived to adulthood and showed biomineralization defects. Fam20b -/-embryos showed severe stunting and increased mortality at E13.5, although early lethality precluded detailed investigations. Physiologic calcification or biomineralization of extracellular matrices is a normal process in the development and functioning of various tissues (eg, bones and teeth). The lesions that developed in teeth, bones, or blood vessels after functional deletion of either Fam20a or Fam20c support a significant role for their encoded proteins in modulating biomineralization processes. Severe amelogenesis imperfecta (AI) was present in both Fam20a and Fam20c null mice. In addition, Fam20a-/-mice developed disseminated calcifications of muscular arteries and intrapulmonary calcifications, similar to those of fetuin-A deficient mice, although they were normocalcemic and normophosphatemic, with normal dentin and bone. Fam20a gene expression was detected in ameloblasts, odontoblasts, and the parathyroid gland, with local and systemic effects suggesting both local and/or systemic effects for FAM20A. In contrast, Fam20c-/-mice lacked ectopic calcifications but were severely hypophosphatemic and developed notable lesions in both dentin and bone to accompany the AI. The bone and dentin lesions, plus the marked hypophosphatemia and elevated serum alkaline phosphatase and FGF23 levels, are indicative of autosomal recessive hypophosphatemic rickets/osteomalacia in Fam20c -/-mice.Keywords amelogenesis imperfecta, knockout, rickets, phosphatonin, ectopic mineralization, biomineralization, dentin, osteomalacia, osteosclerosisThe FAM20 family of secreted proteins in mammals consists of three members (FAM20A, FAM20B, and FAM20C) that were initially thought to have roles in regulating the differentiation and function of hematopoietic and other tissues. 65 Since then, there have been reports linking mutations in both FAM20A and FAM20C to developmental disorders involving bones and/or teeth, suggesting a role for FAM20 proteins in modulating biomineralization processes. In humans, a mutation in FAM20A was recently linked to the occurrence of amelogenesis imperfecta and gingival hyperplasia in a consanguineous family. 69 However, lesions were not reported in bones or teeth of transgenic mice with a partial deletion of Fam20a, and their stunted growth was attributed to malnutrition and an unspecified metabolic disorder. 4 To the best of our knowledge, there have been only two reports elucidating the function FAM20B, which was shown to be a kinase that phosphorylates glycosaminoglycans 50 and in vivo to be involved in cartilage matrix production and skeletal development in zebrafish. 2...

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Section: Discussionmentioning

confidence: 99%

Amelogenesis Imperfecta and Other Biomineralization Defects in Fam20a and Fam20c Null Mice

et al. 2012

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“…The prevalence of AI has been reported as 1:14,000 in the USA (Witkop and Sauk, 1976), 1:8000 in Israel (Chosak et al, 1979), 1:4000 in Sweden (Backman and Holmgren, 1988) and as high as 1:700 in the Vasterbotten county of Sweden (Backman and Holm, 1986). The X-linked form, AIH1, results from mutations in the X-chromosome amelogenin gene (AMELX) and some 12 allelic mutations have already been reported (Hart et al, 2002a,b;Hu and Yamakoshi, 2003).…”

Section: Discussionmentioning

confidence: 99%

Evidence of amelogenesis imperfecta in an early African Homo erectus

Zilberman

Smith

Piperno

et al. 2004

Journal of Human Evolution

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The teeth of the Homo erectus child (Garba IV) recovered from Melka Kunture Ethiopia and dated to 1.5 Ma are characterized by generalized enamel dysplasia, reduced enamel radio-opacity, and severe attrition. This combination of features is found in a large group of hereditary, generalized enamel dysplasias known as amelogenesis imperfecta (AI). SEM studies carried out on epoxy replicas of teeth from the Garba IV child, confirmed that the defects noted were developmental and not due to diagenesis. The enamel prism arrangement is abnormal and there are deep vertical furrows lacking enamel on both buccal and lingual surfaces of all molars. The lesions differ from those characteristic of linear enamel hypoplasia that form discrete horizontal lesions or pits within otherwise normal enamel. We propose that the Garba IV child is the earliest example of AI and provides a link between palaeoanthropology and molecular biology in investigations of the evolutionary history of genetic disorders.

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“…Turkiye Klinikleri J Dental Sci Cases 2015;1 (1) dir. 18,30 Bu çalışmada, Olgu 2'de gözlenen defektlerin mine seviyesinde sınırlı kalması nedeni ile "etch-and-rinse" olarak kullanılabilen bir multimode adeziv sistem ile birlikte kompozit rezin uygulaması yapılmıştır.…”

Section: Resi̇munclassified